bcachefs: Dirent repair code

There was a bug for awhile in previous kernels where we weren't
computing dirent name lengths correctly and we weren't zeroing out
padding at the end of dirents (due to struct bch_dirent changing size by
adding __attribute__((aligned)), and not updating other code to use
offsetof).

This patch fixes dirents with junk at the end, by going off of the
dirent's hash.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 6 insertions, 0 deletions

diff --git a/fs/bcachefs/dirent.h b/fs/bcachefs/dirent.h
index ac28f83d6b2d..30d2143d4ca7 100644
--- a/fs/bcachefs/dirent.h
+++ b/fs/bcachefs/dirent.h
@@ -23,6 +23,12 @@ struct bch_inode_info;
 
 unsigned bch2_dirent_name_bytes(struct bkey_s_c_dirent);
 
+static inline unsigned dirent_val_u64s(unsigned len)
+{
+	return DIV_ROUND_UP(offsetof(struct bch_dirent, d_name) + len,
+			    sizeof(u64));
+}
+
 int __bch2_dirent_create(struct btree_trans *, u64,
 			 const struct bch_hash_info *, u8,
 			 const struct qstr *, u64, int);